The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 18, 1997
Filed:
May. 24, 1995
Hitoshi Kobayashi, Hasuda, JP;
Takao Saito, Hasuda, JP;
Sekisui Chemical Co., Ltd., Osaka, JP;
Abstract
The present invention provides an improved solution casting method to manufacture, with high productivity, a polysulfone resin film superior in quality including appearance, surface smoothness, transparency and thickness accuracy. A polysulfone resin film is cast using the solution casting method in which a solution of polysulfone resin is cast on a support base to a desired thickness, dried to remove the solvent, and resultant resin film is peeled away from the support piece. The solution of polysulfone resin comprises at least one solvent chosen from among anisole, dioxane or tetrahydropyrane. To shorten the drying time even further, at least one solvent chosen from among acetone, methylethylketone, ethyl acetate, toluene and phenol can be mixed in the casting solution of polysulfone resin. The resultant polysulfone film obtained can be uniaxially stretched to produce a high-quality retardation film with superior optical properties.